Table of Contents
- Why Check The pH Of Soap?
- Why Do We Need pH in Soaps?
- How Do You Check The pH Of Soap?
- When Should I Test My Soap pH?
- Why Is The pH Of Soap High?
- Conclusion
Why and How to Check a Soap’s pH? pH levels in soap are crucial because they affect the safety of the soap on the skin.
You’ve researched the safety of lye, tackled the task of using a soap calculator, and made what appears to be a successful batch of soap.
But the question that beckons to all soap makers, me included, is whether it is successful.
Understanding the pH of your soap is paramount. pH, which stands for “potential of hydrogen,” is a measure of the acidity or alkalinity of a solution.
Testing the soap’s pH is a critical part of soap-making to ensure your soap is safe and gentle for use on your skin and within an acceptable pH range.
As you read, we’ll delve into the importance of soap pH, why it matters, and how you can check it effectively.
Let’s start!
Why Check The pH Of Soap?
A couple of things determine whether a bar soap is safe for use. pH is just one of them.
Things like evenness, water or oily bits on the soap’s top, cracks, and much more can be used to check whether a bar soap is safe.
Obviously, if your soap is evenly opaque, has a nice and smooth top, and has no cracks, and you are unsure if it is okay, there are things to do to test it to see if it is.
This is where pH testing comes in.
Soap can range from a pH of 7 to 10, with most soap being 8 to 9. Soaps over 10 are considered lye-heavy and can irritate the skin.
To be on the safe side, you want to check the pH of your soap to ensure it is gentle and effective for use.
The skin’s surface has a natural pH level of around 5.4-6.0, which is slightly acidic depending on your ethnicity, age, and gender, as well as the area of the body, the humidity, and various other factors.
Why Do We Need pH in Soaps?
The pH level of soap we use on our skin matters because our skin is protected from harmful bacteria and other pathogens by a protective acid mantle (that also has a pH).
pH in soaps is essential for several reasons, primarily related to its impact on skin health
Skin Compatibility: The pH level of soap affects its compatibility with the skin’s natural pH.
A soap that closely matches the skin’s pH helps maintain this protective barrier, minimizing the risk of irritation, dryness, and disruption to the skin’s natural microbiome and making it suitable for everyday use, even on sensitive skin.
As a soap maker who desires and is on the path to building a thriving soap business, you want to constantly formulate soaps that are gentle, effective, and compatible with your client’s needs and skin health.
Even though soap is a rinse-off, pH testing your soap assures that your rightly formulated soap is friendly, gentle, and doesn’t make the skin susceptible to skin conditions like acne, eczema, moisture loss, and peeling.
A one-time use of a soap with a high pH value might not affect the skin. However, prolonged use has consequences on the skin’s health.
How Do You Check The pH Of Soap?
As regards the pH test of soap, curing or saponification is critical to arriving at an accurate soap pH testing result.
The pH scale ranges from 1 to 14, with 7 considered neutral. Solutions with a pH less than 7 are acidic, while those with a pH greater than 7 are alkaline.
A soap that is not well saponified will have a high pH level, which is incorrect because it has yet to be fully saponified.
How quickly a soap saponifies appropriately depends on the oils used (or the fatty acid profile of the formula), the soap’s temperature, and the environment.
Testing the pH of bar soap can be done through various methods, each with pros and cons.
Here are different ways to test the pH of bar soap, along with how to get accurate results when using them, and my recommendations for the best and most accurate choice:
pH Testing Strips( both paper and plastic)
Pros:
Easy to use.
Quick results.
Relatively inexpensive.
Cons:
There is no definitive solution ratio of soap to water; How much or how little soap is dispersed in the water can affect the pH reading.
However, you can control the result by accurately measuring soap and water, like 1 gram of soap to 99 grams of distilled water.
Sometimes Limited precision
Best Choice: pH testing strips are suitable for quick and straightforward pH measurements, making them ideal for home use or basic testing needs.
How to Use:
Cut a small piece of soap and dissolve it in distilled water to create a soap solution.
Use a whisk to stir until it dissolves; let it sit undisturbed for maximum dissolution of soap (preferably use boiled distilled water at a temperature of 70°C (158 °F) to quicken the dissolution process).
Dip a pH test strip into the solution and wait a few seconds. Compare the strip’s color to the provided color chart to determine the pH of the soap.
Or just dip your fingers into the water, touch a spot on the soap bar, tap the pH strip on that spot, give it a few seconds, and compare it with the color chart.
The good thing about this second method is you don’t have to worry about water to soap ratio. I do this a lot, and it works well for me.
pH Meter
Pros: Provides accurate and precise pH measurements.
Suitable for professional use and research applications.
Cons:
More expensive than pH testing strips.
Requires calibration and maintenance.
Best Choice: pH meters are the most accurate choice for measuring pH and are suited for professional and beginner soap makers or laboratory settings.
How to Use:
Calibrate the pH meter according to the manufacturer’s instructions.
Prepare a soap solution just like the soap solution for pH Strips.
The standard ratio that you should conduct the pH test is 40° C, which is about 104° F
Submerge the pH meter probe into the soap solution and allow it to stabilize. Voila, your pH result is ready. Record the pH reading displayed on the meter.
Natural Indicators (Red Cabbage Extract)
Pros:
Environmentally friendly and non-toxic.
Can be prepared at home using readily available ingredients.
Cons:
It may provide less precise results compared to other methods.
Color changes may be subtle and require careful observation.
Best Choice: Natural indicators are suitable for educational purposes or when other pH testing methods are unavailable.
How to Use:
Prepare red cabbage extract by boiling red cabbage leaves in water and straining the liquid.
Mix the soap solution with the red cabbage extract.
Observe any color changes in the solution, which indicate the pH of the soap.
Universal Indicator Solution
Pros:
Provides a wide range of pH measurements.
Can detect both acidic and alkaline substances.
Cons:
Requires additional chemical reagents.
Color changes may be less intuitive compared to other methods.
Best Choice: Universal indicator solution is suitable for advanced pH testing needs or when specific pH ranges need to be identified.
How to Use:
Prepare a soap solution and add a few drops of universal indicator solution.
Observe any color changes in the solution and match them to the provided color chart to determine the pH of the soap.
Old-School Tongue Test:
– While not the most scientific method, it’s a fun way to get a rough idea of soap pH.
– Lick the soap or hold it up to the tip of your tongue (yes, really!) and pay attention to how it feels on your tongue.
If the soap isn’t fully saponified, you will get a bit of a zapping or astringent taste on your tongue (by the way, it will not hurt you).
But if it tastes soapy and is not zappy, it’s pretty good.
When Should I Test My Soap pH?
After Saponification: The chemical process where lye and oils turn into soap usually takes 24-48 hours, depending on the ingredient, oils, and climate. After this time, test the pH.
The pH further lowers during the 4-6 weeks of curing. Before using your soap or offering it for sale, test the pH one final time to ensure that it meets your quality standards.
Why Is The pH Of Soap High?
There are several reasons why the pH of a bar soap could be high. One is wrong timing. Checking the soap’s pH before it is fully saponified results in a high pH.
Consequently, if after letting the soap cure for 4-8 weeks maximum, it still shows a high pH, then there is something wrong with either your ingredient.
There is a high probability that you had a false trace while making the soap, that the soap contains heavy lye, or that the soap wasn’t emulsified correctly.
False Trace often happens due to Rapid changes in temperature, such as sudden cooling, which can cause the fats/oils to thicken temporarily, giving the illusion of Trace.
This occurs mainly when using saturated fats like shea butter and beeswax. Etc.
To balance the pH in soap, after a soap batch is fully saponified and still showing signs of high pH, knowing the cause of the high pH would be amazing before taking any drastic action.
That will help you pick a suitable solution. Even if you don’t know what went wrong, rebatching the soap is a fantastic option.
Some people say to add lemon or lime juice to lower the pH of the soap. The issue with this is that both are acidic and depending on your ingredients, they might not suit your soap recipe.
So, instead of adding lemon or lime juice, rebatching, paying keen attention to the ingredients, and mixing well is best.
Consequently, meticulously measuring the ingredients and following a well-organized soap-making process, I find that you seldom encounter high soap pH, and the soap’s pH is more often accurate.
Conclusion
Checking the pH of your soap is a crucial step in ensuring its safety and effectiveness for use on your skin.
Even though there are lots of variables to determine if a bar soap is safe or not,
By understanding the importance of pH and following the steps outlined in this guide, you can confidently assess the pH of your soap and make any necessary adjustments to create high-quality, skin-friendly products.
Remember, a balanced pH cleanses and cares for your skin, leaving it healthy and nourished with every use.
